Neurogenesis decreases with age in the canine hippocampus and correlates with cognitive function

New neurons are continually produced in the adult mammalian brain from progenitor cells located in specific brain regions, including the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. We hypothesized that neurogenesis occurs in the canine brain and is reduced with age. We examined neurogenesis in the hippocampus of five young and five aged animals using doublecortin (DCX) and bromodeoxyuridine (BrdU) immunostaining. The total unilateral number of new neurons in the canine SGZ and granule cell layer (GCL) was estimated using stereological techniques based upon unbiased principles of systematic uniformly random sampling. Animals received 25mg/kg of BrdU once a day for 5 days and were euthanized 9 days after the last injection. We found evidence of neurogenesis in the canine brain and that cell genesis and neurogenesis are greatly reduced in the SGZ/GCL of aged animals compared to young. We further tested the hypothesis that an antioxidant fortified food or behavioral enrichment would improve neurogenesis in the aged canine brain and neurogenesis may correlate with cognitive function. Aged animals were treated for 2.8 years and tissue was available for six that received the antioxidant food, five that received the enrichment and six receiving both treatments. There were no significant differences in the absolute number of DCX or DCX-BrdU neurons or BrdU nuclei between the treatment groups compared to control animals. The number of DCX-positive neurons and double-labeled DCX-BrdU-positive neurons, but not BrdU-positive nuclei alone, significantly correlated with performance on several cognitive tasks including spatial memory and discrimination learning. These results suggest that new neurons in the aged canine dentate gyrus may participate in modulating cognitive functions.     

Interpersonal factors and perinatal depressive symptomatology in a low-income Latina sample

Interpersonal factors are among the risk factors that predispose women to experiencing mood disturbances during the childbearing years. This study investigates the trajectory of change in depressive symptomatology over the course of the perinatal period as related to interpersonal risk factors (marital quality and social support) in a sample of 69 low-income, mostly immigrant Latina mothers at high and low risk for depression. We found a significant linear change in depressive symptomatology from baseline (pregnancy) through the postpartum period. This decline was steeper for high-risk women who reported high levels of social support compared with those who reported low levels of social support. In addition, a greater decline in depressive symptom scores was found for women who reported better postnatal marital quality, irrespective of risk group status. The results suggest the importance of considering marital quality and social support in estimations of risk for depression. These findings also have implications for targeting social support and marital quality in preventive interventions for perinatal depression in Latinas.     

Socioeconomic gradients predict individual differences in neurocognitive abilities

Socioeconomic status (SES) is associated with childhood cognitive achievement. In previous research we found that this association shows neural specificity; specifically we found that groups of low and middle SES children differed disproportionately in perisylvian/language and prefrontal/executive abilities relative to other neurocognitive abilities. Here we address several new questions: To what extent does this disparity between groups reflect a gradient of SES‐related individual differences in neurocognitive development, as opposed to a more categorical difference? What other neurocognitive systems differ across individuals as a function of SES? Does linguistic ability mediate SES differences in other systems? And how do specific prefrontal/executive subsystems vary with SES? One hundred and fifty healthy, socioeconomically diverse first‐graders were administered tasks tapping language, visuospatial skills, memory, working memory, cognitive control, and reward processing. SES explained over 30% of the variance in language, and a smaller but highly significant portion of the variance in most other systems. Statistically mediating factors and possible interventional approaches are discussed.     

Dissemination of effective mental health treatment procedures: Maximizing the return on a significant investment

While much is known about the efficacy of evidence-based practices, it is currently less clear how to implement these practices into the broader mental health system. Dissemination and implementation research will play a critical role in addressing this uncertainty. This commentary reviews the most recent and compelling research related to these topics while advocating a broader and more defined perspective of dissemination for future research. Three of the authors' most pressing questions are proposed and explored.     

An in-situ examination of the timing of information pick-up for interception by cricket batsmen of different skill levels

ObjectivesCricket batting is performed under demanding constraints, which requires rapid and accurate decision making for successful achievement of the skill goal. To understand how batsmen negotiate these constraints, the capability of highly skilled and low skilled cricket batsmen to utilise visual information prior to and during sections of ball flight to strike balls delivered by fast bowlers was examined.MethodSix highly skilled and six low skilled batsmen faced different types of balls delivered by three fast bowlers. Batsmen wore vision occlusion spectacles and were required to strike delivered balls, while their vision of the bowler's delivery action and ball flight was selectively occluded. Three vision conditions were randomly designed that included temporal occlusion at: (i) a point prior to ball release (providing only advance information), (ii) a point prior to ball bounce (providing advance and ball flight information) and (iii) no occlusion (where all advance, ball flight and bounce information were visible). Foot movements made forward or backward were assessed as a measure of ball length judgement, while the quality of bat–ball contact was assessed as a measure of interception.ResultsResults demonstrated the superior capability of highly skilled batsmen to utilise information prior to ball release to judge short ball length. Expert batsmen were better able to utilise ball flight information prior to and post-bounce to attain a superior number of bat–ball contacts.ConclusionsFindings demonstrate that the mechanism of experts to deal with task constraints when attempting to intercept a delivered ball is their capability to pick-up visual information to judge ball landing position.     

The eyes or the mouth? Feature salience and unfamiliar face processing in Williams syndrome and autism

Using traditional face perception paradigms the current study explores unfamiliar face processing in two neurodevelopmental disorders. Previous research indicates that autism and Williams syndrome (WS) are both associated with atypical face processing strategies. The current research involves these groups in an exploration of feature salience for processing the eye and mouth regions of unfamiliar faces. The tasks specifically probe unfamiliar face matching by using (a) upper or lower face features, (b) the Thatcher illusion, and (c) featural and configural face modifications to the eye and mouth regions. Across tasks, individuals with WS mirror the typical pattern of performance, with greater accuracy for matching faces using the upper than using the lower features, susceptibility to the Thatcher illusion, and greater detection of eye than mouth modifications. Participants with autism show a generalized performance decrement alongside atypicalities, deficits for utilizing the eye region, and configural face cues to match unfamiliar faces. The results are discussed in terms of feature salience, structural encoding, and the phenotypes typically associated with these neurodevelopmental disorders.     

Successive incrementing non-matching-to-samples in rats: An automated version of the odor span task

The odor span task is a procedure frequently used to study remembering of multiple stimuli in rodents. A large arena is used and odor stimuli are presented using scented cups. Selection of each odor is reinforced when first presented, but not on subsequent presentations; correct selections depend on remembering which stimuli were previously presented. The use of an arena setting with manual stimulus presentation makes the odor span task labor-intensive and limits experimental control; thus, an automated version of the task would be of value. The present study used an operant chamber equipped with an olfactometer and trained rats using successive conditional discrimination procedures under an incrementing non-matching-to-samples contingency. High rates of responding developed to odor stimuli when they were session-novel with low rates of responding to subsequent presentations of that odor. Additional experiments assessed variations of the procedure to determine the role of the frequency of odor presentation and the retention interval separating sample and comparison. Discrimination was impaired with long retention intervals suggesting the importance of this variable. These findings confirmed that rats differentiate between stimuli that are session-novel and those previously encountered and support the use of an automated procedure as an alternative to the odor span task.